Theft of vehicles and particularly commercial trucks and heavy equipment is a wide spread problem. Most heavy equipment must be left on a job site and hence over-night thefts are a problem. Theft of heavy equipment is made relatively simple by use of duplicate keys or hot-wiring about the ignition.
In the present invention a lock mechanism is provided which cannot be easily cut with a saw, cutting torch or drill and thus will resist all but the most determined thiefs. This is because removal or cutting of the fuel line makes it difficult to start the equipment, particularly diesel equipment for a substantial period of time.